Study of Opuntia humifusa: phytochemical analysis of aqueous fruit extract and green synthesis of Ag2O nanoparticles

Ag₂O nanoparticle synthesis was carried out via co-precipitation technique based on using AgNO₃ and secondary metabolites present in the aqueous extract of Opuntia humifusa fruit for the first time. The amount of measured total phenol, flavonoid content, flavone, and flavonol content, and anthocyanin were 38.46 μg eq gallic acid mg⁻¹ extract, 8.34 μg eq quercetin mg⁻¹ extract, 0.614 μg eq quercetin mg⁻¹ DW, and 3.1 mmol L⁻¹, respectively. Moreover, the predominant phenolic compound was gallic acid. Catechin and chlorogenic acid were found in both fruit juice and fruit aqueous extract. Scanning electron microscopy (SEM) of Ag₂O-NPs showed the average particle size was 10.58 nm. Scanning electron microscopy, X-ray diffraction Spectroscopy, and UV/visible spectrometry also confirmed the synthesis. This study then focuses on IC₅₀ and NO amount differences before and after the synthesis of Ag₂O-NPs which were 448.29 and 101.38 μg mL⁻¹ for IC₅₀ and 35.7% and 62.6% for NO, respectively.